Trends in sex-based differences in outcomes following coronary artery bypass grafting in the United States between 2004 and 2015

Improving diversity in cardiac surgery clinical trials with ROMA:Women as an exemplar

PURPOSE OF REVIEW

To describe methods to improve representation of women in cardiac surgery clinical trials.

RECENT FINDINGS

Cardiovascular disease risk among women is high. Historically, women have been excluded from cardiac surgery trials, in part due to restrictive inclusion criteria. Surgical outcomes, specifically after coronary artery bypass grafting, are consistently worse among female patients, and these outcomes have not improved over the last decade. Addressing treatment effects and clinical benefit among women requires accurate representation in cardiovascular surgery trials. ROMA:Women, is the first cardiac surgery trial to focus solely on women, with the goal of addressing underrepresentation. Through utilizing specific strategies, ROMA:Women is a promising first step in advancing health equity.

SUMMARY

Strategies to ensure effective recruitment and representation among women in cardiac surgery clinical trials, such as tailored eligibility criteria and comprehensive strategies to improve communication and increase trust, are two of many potential approaches to address the structural barriers to female representation in cardiac surgery clinical trials. To date, ROMA:Women is an example of a trial that has shown extraordinary preliminary success enrolling women. Designing trials exclusively for women is one strategy to improve the diversity of clinical trial participation.

Contemporary socioeconomic-based disparities in cardiac surgery: Are we closing the disparities gap?

OBJECTIVE

Female sex and lower income residence location are associated with worse health care outcomes. In this study we analyzed the national, contemporary status of socioeconomic disparities in cardiac surgery.

METHODS

Adult patients within the Nationwide Readmissions Database who underwent coronary artery bypass grafting (CABG), surgical aortic valve replacement (SAVR), mitral valve (MV) replacement, MV repair, or ascending aorta surgery from 2016 to 2018 were included. Sex and median household income quartile (MHIQ) were compared within each surgery group. Primary outcome was 30-day mortality. Multivariable analysis was adjusted for patient characteristics and hospital-level factors.

RESULTS

A weighted total of 358,762 patients were included. Fewer women underwent CABG (22.3%), SAVR (32.2%), MV repair (37.5%), and ascending aorta surgery (29.7%). In adjusted analysis, female sex was independently associated with higher 30-day mortality rates after CABG (adjusted odds ratio [aOR], 1.6), SAVR (aOR, 1.4), MV repair (aOR, 1.8), and ascending aorta surgery (aOR, 1.2; all P < .03). The lowest MHIQ was independently associated with higher 30-day mortality rates after CABG (aOR, 1.4), SAVR (aOR, 1.5), MV replacement (aOR, 1.3), and ascending aorta surgery (aOR, 1.8; all P < .004) compared with the highest quartile. Women were less likely to receive care at urban and academic hospitals for CABG compared with men. Patients of lower MHIQ received less care at urban and academic institutions for all surgeries.

CONCLUSIONS

Despite advances in the techniques and safety, women and patients of lower socioeconomic status continue to have worse outcomes after cardiac surgery. These persistent disparities warrant the need for root cause analysis.

Health Inequities in Coronary Artery Bypass Grafting Literature: A Scoping Review

Although life saving, health inequities exist regarding access and patient outcomes in Coronary artery bypass grafting (CABG), especially among marginalized groups. This scoping review's goal is to outline existing literature and highlight gaps for future research. Researchers followed guidance from the Joanna Briggs Institute and PRISMA extension for scoping reviews. We conducted a search to identify articles published between 2016 and 2022 regarding CABG and inequity groups, defined by the National Institutes of Health. Fifty-seven articles were included in our final sample. Race/Ethnicity was examined in 39 incidences, Sex or Gender 29 times, Income 17 instances, Geography 10 instances, and Education Level 3 instances. Occupation Status 2 instances, and LGBTQ+ 0 times. Important disparities exist regarding CABG access and outcomes, especially involving members of the LGBTQ+, Native American, and Black communities. Further research is needed to address health disparities and their root causes for focused action and improved health of minoritized groups.

Sex differences in coronary artery bypass grafting-related morbidity and mortality

Background

Coronary artery bypass grafting (CABG) is associated with both cardiovascular disease (CVD) and non-CVD traits. In addition, women’s prognosis after coronary events and revascularizations is worse than in men. As the course of CVD in women differs from that of men, we performed a phenome-wide analysis on the sex differences in CABG -related morbidity and mortality.

Materials and methods

We performed an untargeted analysis on the sex differences in predictors and outcomes of CABG. We studied a sample of 176,680 FinnGen participants, including 5,950 individuals who underwent CABG (4,988 men and 962 women) and were followed between 1998 and 2019. Over 1,100 different traits were analyzed for both sexes and the results were adjusted with age, smoking status and BMI. Cox proportional hazards models with sex-trait interactions were used to estimate the associations between (1) traits and incident CABG; and (2) CABG and incident traits.

Results

In women, CABG was more strongly related to greater increases in risk of diseases such as hypertension, Alzheimer’s, aortic aneurysms, gout, and chronic kidney disease compared to risk increases observed in men (all interaction p-values &lt; 0.03). After CABG, men had 2.5-fold (p = 3.1E−15) and women 6.3-fold (p = 9.4E−08) greater risk of cardiac death compared to same-sex individuals who did not undergo CABG (p for interaction 8.2E−4). Moreover, the risk of death in women remained higher even 12 years after CABG, whereas the long-term risk of death in men was not increased, compared to same-sex individuals who did not undergo CABG.

Conclusion

The adverse outcomes after CABG, both quantity and quality, also appear to differ between men and women. In women, CABG is related to greater long-term increases in risk of cardiac death and several other disease states than in men. Consideration should therefore be given to whether women receive adequate long-term post-operative therapy and follow-up as CABG is not associated with equally improved cardiovascular disease prognosis in women than in men.

Females have an increased risk of short-term mortality after cardiac surgery compared to males: Insights from a national database

OBJECTIVES

Female sex is considered a risk factor for mortality and morbidity following cardiac surgery. This study is the first to review the UK adult cardiac surgery national database to compare outcomes following surgical coronary revascularisation and valvular procedures between females and males.

METHODS

Using data from National Adult Cardiac Surgery Audit, we identified all elective and urgent, isolated coronary artery by-pass grafting (CABG), aortic valve replacement (AVR) and mitral valve replacement/repair (MVR) procedures from 2010 to 2018. We compared baseline data, operative data and outcomes of mortality, stroke, renal failure, deep sternal wound infection, return to theater for bleeding, and length of hospital stay. Multivariable mixed-effect logistical/linear regression models were used to assess relationships between sex and outcomes, adjusting for baseline characteristics.

RESULTS

Females, compared to males, had greater odds of experiencing 30-day mortality (CABG odd ratio [OR] 1.76, confidence interval [CI] 1.47-2.09, p < .001; AVR OR 1.59, CI 1.27-1.99, p < .001; MVR OR 1.37, CI 1.09-1.71, p = .006). After CABG, females also had higher rates of postoperative dialysis (OR 1.31, CI 1.12-1.52, p < .001), deep sternal wound infections (OR 1.43, CI 1.11-1.83, p = .005) and longer length of hospital stay (β 1.2, CI 1.0-1.4, p < .001) compared to males. Female sex was protective against returning to theater for postoperative bleeding following CABG (OR 0.76, CI 0.65-0.87, p < .001) and AVR (OR 0.72, CI 0.61-0.84, p < .001).

CONCLUSION

Females in the United Kingdom have an increased risk of short-term mortality after cardiac surgery compared to males. This highlights the need to focus on the understanding of the causes behind these disparities and implementation of strategies to improve outcomes in females.

Trends of Sex Differences in Clinical Outcomes After Myocardial Infarction in the United States

BACKGROUND

Female patients have been shown to experience worse clinical outcomes after acute myocardial infarction (AMI) compared with male patients. However, it is unclear what trend these differences followed over time.

METHODS

Data from patients hospitalized with AMI between 2004 and 2015 in the National Inpatient Sample were retrospectively analyzed, stratified according to sex. Multivariable logistic regression analyses were performed to examine the adjusted odds ratios (aORs) of invasive management and in-hospital outcomes according to sex. The Mantel-Haenszel extension of the χ2 test was performed to examine the trend of management and in-hospital outcomes over the study period.

RESULTS

Of 7,026,432 AMI hospitalizations, 39.7% (n = 2,789,494) were women. Overall, women were older (median: 77 vs 70 years), with a higher prevalence of risk factors such as diabetes, hypertension, and depression. Women were less likely to receive coronary angiography (aOR, 0.92; 95% confidence interval [CI], 0.91-0.93) and percutaneous coronary intervention (aOR, 0.82; 95% CI, 0.81-0.83) compared with men. Odds of all-cause mortality were higher in women (aOR, 1.03; 95% CI, 1.02-1.04; P < 0.001) and these rates have not narrowed over time (2004 vs 2015: aOR, 1.07 [95% CI, 1.04-1.09] vs 1.11 [95% CI, 1.07-1.15), with similar observations recorded for major adverse cardiovascular and cerebrovascular events.

CONCLUSIONS

In this temporal analysis of AMI hospitalizations over 12 years, we showed lower receipt of invasive therapies and higher mortality rates in women, with no change in temporal trends. There needs to be a systematic and consistent effort toward exploring these disparities to identify strategies to mitigate them.

Impact of sex on outcomes after cardiac surgery: A systematic review and meta-analysis

BACKGROUND

Despite advances in cardiac surgery, observational studies suggest that females have poorer post-operative outcomes than males. This study is the first to review sex related outcomes following both coronary artery bypass graft (CABG) and valve surgery with or without combined CABG.

METHODS

We identified 30 primary research articles reporting either short-term mortality (in-hospital/30 day), long-term mortality, and post-operative stroke, sternal wound infection and myocardial infarction (MI) in both sexes following CABG and valve surgery with or without combined CABG. Reported adjusted odds/hazard ratio were pooled using an inverse variance model.

RESULTS

Females undergoing CABG and combined valve and CABG surgery were at higher risk of short-term mortality (odds ratio (OR) 1.40; 95% confidence interval (CI) 1.32-1.49; I² = 79%) and post-operative stroke (OR 1.2; CI 1.07-1.34; I² = 90%) when compared to males. However, for isolated AVR, there was no difference found (OR 1.19; 95% CI 0.74-1.89). There was no increased risk in long-term mortality (OR 1.04; 95% CI: 0.93-1.16; I² = 82%), post-operative MI (OR 1.22; 95%CI: 0.89-1.67; I² = 60%) or deep sternal wound infection (OR 0.92; 95%CI: 0.65-1.03, I² = 87%). No evidence of publication bias or small study effect was found.

CONCLUSION

Females are at a greater risk of short-term mortality and post-operative stroke than males following CABG and valve surgery combined with CABG. However, there is no difference for Isolated AVR. Long-term mortality is equivalent in both sexes. PROSPERO Registration: CRD42021244603.

Gender Differences in Failure-to-Rescue After Coronary Artery Bypass Grafting

BACKGROUND

Female patients experience worse outcomes following coronary artery bypass grafting (CABG). We investigated whether rates of failure-to-rescue (FTR), a systems-based quality indicator, were greater in women who underwent CABG.

METHODS

A retrospective review was conducted on 20,045 patients who underwent isolated, non-emergent CABG between January 2002 and August 2019 at a single academic center. FTR was defined as postoperative death within 30 days after stroke, renal failure, reoperation, and prolonged ventilation. Propensity-score matching was performed utilizing preoperative variables, excluding gender.

RESULTS

4,980 propensity-score matched pairs were identified. In the matched analysis, women experienced higher rates of postoperative stroke (1.9% vs. 1.2%; p = 0.008), prolonged ventilation (13.3% vs. 10.0%, p < 0.001), and 30-day mortality (2.6% vs. 1.8%; p = 0.01). Rates of FTR following stroke (p = 0.36), renal failure (p = 0.11), reoperation (p = 0.86), and prolonged ventilation (p = 0.48) were not statistically significant between female and male patients.

CONCLUSIONS

Women who underwent isolated, non-emergent CABG had statistically similar frequencies of FTR compared to their male counterparts despite experiencing greater rates of morbidity and mortality. Further efforts to narrow the gender outcome gap after CABG should focus on preoperative and intraoperative phases of care instead of postoperative management.

Sex Differences in Coronary Artery Bypass Grafting Techniques: A STS Database Analysis

BACKGROUND

Females with coronary artery disease (CAD) have inferior outcomes compared with males, including higher mortality following coronary artery bypass grafting (CABG). We aimed to evaluate the association of female sex with the use of guideline-concordant CABG revascularization techniques.

METHODS

The Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database was queried for adult patients who underwent first-time isolated CABG in the US from 2011-2019. The association between female sex and the odds of (1) receiving a left internal mammary artery (LIMA) graft for revascularization of the left anterior descending (LAD) artery, (2) undergoing complete revascularization, and (3) undergoing multi-arterial grafting was assessed, adjusting for procedural anatomy.

RESULTS

Among 1,212,487 patients meeting inclusion criteria, 75% were male (n=911,178) and 25% were female (n=301,309). Female sex was associated with lower unadjusted rates of revascularization with an IMA (93.9% vs 95.9%, P<.001), bilateral IMA (2.9% vs 5.6%, P<.001) or radial artery (3.2% vs 5.6%, P<.001) graft. After adjustment, females had a lower odds than males of receiving a LIMA graft to the LAD (adjusted odds ratio [AOR] 0.79, 95% CI 0.75-0.83, P<.001), undergoing complete revascularization (AOR 0.86, 95% CI 0.83-0.90, P<.001), and undergoing multi-arterial grafting (AOR 0.78, 95% CI 0.75-0.81, P<.001).

CONCLUSIONS

Female sex was associated with a 14-22% lower odds of undergoing guideline concordant revascularization including LIMA to LAD grafting, multi-arterial grafting, and complete revascularization. Further investigation is necessary to determine why revascularization approaches differ by sex and to what degree sex disparities in CAD outcomes are due to surgical approach.